Genetics of Corn Corn is one of the world’s most important food crops. It has been subject to selective breeding techniques and hybridization for many years, which have resulted in vigorous,...

Please answer


Genetics of Corn Corn is one of the world’s most important food crops. It has been subject to selective breeding techniques and hybridization for many years, which have resulted in vigorous, high- yielding varieties. Nearly all corn grown today is hybrid corn. Some varieties of corn are chosen for their sweet flavour while the mixed coloration of the Indian corn varieties makes them popular decorations during the autumn months. Purpose: To determine the probable genotypes of parents by examining the phenotypes of corn for two different and independently assorted traits. Materials: Corn Ears (Figures 1, 2, 3 and 4) Procedure: [18 marks - TI] 1. Look at sample 1 corn ear. The kernels display two different traits whose genes are located different chromosome. 2. Describe the two different traits: colour and shape. Predict which phenotypes are dominant and which are recessive.  Colour: _______________________ Dominant and __________________________ Recessive Shape:_______________________ Dominant and ___________________________Recessive 3. For each of the corn samples, count at least 100 kernels, and complete the associated table. Use P to represent the dominant colour and p to represent the recessive colour. Use S to represent the dominant shape and s to represent the recessive shape. • Genotype: Please indicate one possible genotype that would produce the specified phenotype. • Number: Indicate how many kernels of corn you counted that fit the specified phenotype • Ratio: Look across all 4 phenotypes and approximate a Mendelian Ratio. Corn Sample 1:  Phenotype Genotype Number Ratio Dominant alleles for colour and shape Dominant allele for colour, but recessive allele for shape Recessive allele for colour, but dominant allele for shape Recessive allele for colour and shape Corn Sample 2:  Phenotype Genotype Number Ratio Dominant alleles for colour and shape Dominant allele for colour, but recessive allele for shape Recessive allele for colour, but dominant allele for shape Recessive allele for colour and shape Corn Sample 3:  Phenotype Genotype Number Ratio Dominant alleles for colour and shape Dominant allele for colour, but recessive allele for shape Recessive allele for colour, but dominant allele for shape Recessive allele for colour and shape Corn Sample 4:  Phenotype Genotype Number Ratio Dominant alleles for colour and shape Dominant allele for colour, but recessive allele for shape Recessive allele for colour, but dominant allele for shape Recessive allele for colour and shape Results: [8 marks - COMM] What are the possible genotypes of the parents of each sample of corn? Prove it using punnet squares  Sample Genotype Parent 1 Parent 2 1 2 3 4 Proof: Analysis: [8 marks - APP] 1. Compare and contrast the results from all four corn samples  2. Would the results be any different if you took larger samples of corn (i.e., counted more kernels) or looked at multiple cobs and averaged the results? Why would this be?  3. Were there any corn cobs that seemed to demonstrate monohybrid characteristics? Were there any corn cobs that seemed to demonstrate dihybrid characteristics? Explain.  Expansion: [8 marks - KU] 1. A corn that is homozygous dominant for colour and recessive for shape is crossed with another corn that is recessive for colour and homozygous dominant for shape. Using a punnet square, what are the expected genotype and phenotype of the F1 generation resulting from this cross?  2. Take two offspring from the F1 cross (question 1); what is the expected phenotypic ratio for a cross between these two offspring? Support your answer with a punnet square  Sample 1 Yellow, Smooth Purple, Wrinkled Purple, Smooth Yellow, Wrinkled Smooth Wrinkled Sample 2 Purple, Smooth Purple, Wrinkled Sample 3 Sample 4